While riding the Colorado National Monument loop (aka "Tour of the Moon", or Rimrock Drive) yesterday I had a chance to talk with a few of the park rangers at the entrance stations and at the visitor's center. The Colorado National Monument administration has decided to start enforcing the rule that states that all bicyclists must have either lights or reflectors on their bikes in order to ride over the Monument starting within the next month or so. This rule on been "on the books" for quite some time, but they have only recently decided to start vigorously enforcing it.
There is some confusion even among the park staff as to exactly what is required. A law enforcement ranger, Clint Forte, told me that lights will be required and that reflectors will not cut it; however, yesterday I was showed the most recent memo that stated "lights or reflectors" but didn't specify if that meant both front and rear. Further confusing matters, one of the park people said that just a tail light or reflector is required, while another said that something front and rear is going to be required. So apparently even they don't know yet exactly what they're doing. Furthermore, I asked one of the rangers how they plan on dealing with tourists who are wanting to ride through the park and are unfamiliar with the new rule enforcement; her reply was, "We're still working on that."
So to play it safe, I would plan on using both a front head light and tail light. I had a Planet Bike Spok tail light on yesterday, which seemed to more than meet the requirement. Likewise for the Planet Bike Spok head light, since what they want is for bicyclists to be visible to motorists. ($20 at REI, http://ecom1.planetbike.com/3042_1.html)
For those of you unfamiliar with this ride, it is truly one of the crown jewels of road riding in Colorado. It is a spectacular ride, with amazing views of red rock canyons and some really good climbing. The ride include three unlit tunnels, one on the east side and two on the west, which is why the Park Service wants us to use the lights. This ride featured as a stage for several editions of the Coors Classic in the 1980s and was in the film American Flyers. A map of the ride can be found here: http://www.tomorrowhillfarm.com/John...cycleMaps.html
It seems to me that the park staff has developed a rather antagonistic relationship with cyclists recently, with the park superintendent even going so far a year ago as to suggest that the park may be closed to cyclists (there is precedent for this elsewhere in the National Park Service). So far that hasn't happened, but the park has made it abundantly clear (in my opinion) that they regard cyclists as a nuisance and that we're second class users of the park compared to those in a motorized vehicle (part of the price for be slower than a car on the climbs, I guess). So it's important for us to play nice and obey their rules. I also suspect that the park would have no hesitation about turning away any cyclists without lights.
When I find out from the Park Service exactly what they're requiring I'll pass that information along. Meanwhile, it looks like a little LED light front and rear will make them happy with you.